Ophthalmic Objective Optics for Wide-Field Fundus Imaging
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Solution Overview
Problem
Existing ophthalmic devices face challenges in achieving a wide field of view for fundus observation while maintaining a compact and cost-effective optical structure, and in optimizing pupil aberration to prevent vignetting of scanning light at the pupil.
Innovation Solution
The ophthalmic device employs an objective lens with specific lens configurations that satisfy conditional expressions for lens thickness and angular magnification ratios, ensuring a medium-angle field of view and effective light transmission, while using a shared optical system for both scanning laser ophthalmoscopy and optical coherence tomography.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the objective optical system uses a compact lens configuration, then the device size is reduced and cost is lowered, but the field of view becomes narrow and vignetting occurs
Solution Approach 1:
The patent applies parameter changes by precisely controlling the ratio of lens thickness sum to working distance (0.1 ≤ D/L ≤ 0.25) and angular magnification ratio (0.5 ≤ |β1/β2| ≤ 2.0). These parameter optimizations enable a compact lens configuration that achieves both reduced device size and adequate field of view without vignetting, resolving the contradiction between compactness and observation area.
2Volume of moving object
If the objective optical system uses a compact lens configuration, then the device size is reduced and cost is lowered, but pupil aberration increases causing vignetting of scanning light
Solution Approach 1:
The patent controls pupil aberration through parameter optimization, specifically maintaining the lens thickness sum to working distance ratio within 0.1 ≤ D/L ≤ 0.25 and angular magnification ratio within 0.5 ≤ |β1/β2| ≤ 2.0. These parameter constraints ensure that even in compact configurations, pupil aberration remains within acceptable limits to prevent vignetting of scanning light.
3Area of stationary object
If the objective optical system uses a complex lens arrangement, then field of view and optical performance are improved, but device complexity and cost increase
Solution Approach 1:
The patent achieves adequate field of view with simplified optical structure by optimizing key parameters: the lens thickness sum to working distance ratio (0.1 ≤ D/L ≤ 0.25) and angular magnification ratio (0.5 ≤ |β1/β2| ≤ 2.0). This parameter-based approach allows achieving acceptable optical performance without requiring complex multi-element lens arrangements, thereby reducing device complexity and cost.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration allows for efficient, wide-field fundus imaging with reduced vignetting and lower costs by optimizing lens arrangements and angular magnification, enabling comprehensive fundus observation with improved optical efficiency.
Implementation Method 1
an objective optical system having lens groups that form a pupil, which has a conjugate relationship with a pupil of an subject eye, at the scanning section
Data Source
AI summary
An ophthalmic optical system for observing an subject eye, including: an objective optical system that forms a pupil that has a conjugate relationship with a pupil of the subject eye, wherein, given that a distance from a pupil position that has a conjugate relationship with the pupil of the subject eye to the pupil of the subject eye is L, and a sum of central thicknesses of lenses included in the objective optical system is D, a conditional expression expressed by0.1≤D/L≤0.25is satisfied.